Hydrocarbons in Intertidal Sediments and Mussels from Prince William Sound, Alaska, 1977-1980: Characterization and Probable Sources

uses the NOAA Technical Memorandum series to issue informal scientific and technical publications when complete formal review and editorial processing are not appropriate or feasible. Documents within this series reflect sound professional work and may be referenced in the formal scientific and technical literature. Notice to Users of this Document This document is being made available in .PDF format for the convenience of users; however, the accuracy and correctness of the document can only be certified as was presented in the original hard copy format. iii We collected and analyzed samples of sediments and mussels (Mytilus trossulus) for alkane and aromatic hydrocarbons from eight sampling stations adjacent to the oil tanker vessel transportation corridor through Prince William Sound, Alaska, during the period from 1977 to 1980, to determine baselines prior to the start of oil tanker movement through the Sound. We' evaluated interannual variability of these analytes using a two-factor analysis of variance of logarithm-transformed hydrocarbon concentrations determined in duplicate samples collected in June 1977 and in June 1978 at six of the stations. Intra-annual variability was evaluated using analyses of duplicate samples collected in May, June, and August 1978 at seven of the stations. In addition, total organic carbon and grain size distribution was determined in the sediment samples, the lipid content was determined in the mussel samples, and the surface seawater temperature and salinity was determined for each sampling station. The hydrocarbon analyses indicated chronic, low-level hydrocarbon contamination that probably originates from small fuel spills, ballast water discharges, and fuel-combustion exhaust emissions of occasional vessel activity adjacent to three of the sampling stations: Constantine Harbor, Rocky Bay, and Mineral Flats, in decreasing order of contamination, respectively. Sediments at these three stations were contaminated by aromatic hydrocarbons found at concentrations that were generally less than 10 ng/g dry sediment weight, but above detectable limits (< 1.0 ng/g). In contrast, the remaining five stations showed no indication of petroleum hydrocarbon contamination, primarily because detected aromatic hydrocarbons were present only sporadically and at concentrations that were generally near detection limits. Both perylene, which was found at concentrations well above detection limits at all stations outside Port Valdez, and phenanthrene, which was also found sporadically at all sampling stations may have natural sources. Concentrations of aromatic hydrocarbons were frequently too low at most of the sampling stations to allow evaluation of intra-and interannual variability. Concentrations of individual n-alkanes varied substantially in sediments …